U.S. National Team coach Bob Bradley rested his biggest stars in Saturday’s exhibition vs. Spain, and the result was a humbling 4-0 emasculation at the hands _ or feet _ of the World Cup champions. He’ll find out if it was worth it Tuesday in Detroit (8 p.m., FSC), when the U.S. opens the Gold Cup against Canada.

Winning this tourney has always been Bradley’s top summer goal, more than an upset in a friendly, no matter how hyped the opponent. To that end he rested Landon Donovan, Clint Dempsey, Michael Bradley, Carlos Boganegra and Steve Cherundolo, saw a young team get mauled all to be ready for the next three weeks.

“We know it’s going to be a tough tournament but we want to do well and we want to win it. That’s the objective and the first game is Canada and that’s what we’re concentrating on right now. We need to start the Gold Cup off on a good note and win the first game,’’ said Dempsey, who came on a second-half sub Saturday.

“Bob talked to me before the game. I knew I wasn’t going to play 90 minutes. It didn’t make much sense because I played a long season in England; and looking toward the Gold Cup, you want to make sure you’re fresh for that, because there are still a lot of games to be played for that.’’

Or so they hope. They’ve never lost a group stage game in the Gold Cup, and after facing Canada they’ll play Panama Saturday in Tampa and Guadeloupe on June 14, all in Group C with the top two teams automatically reaching the quarterfinals.

They have their sights firmly planted on the June 25 final in the Rose Bowl and reclaiming the crown they won in 2005 and ’07. Rival Mexico _ who beat them 5-0 in the 2009 final _ already sent a shot across the bow with a Chicharito hat-trick and 5-0 rout of El Salvador, and seems determined to await the U.S. in Pasadena.

“It’s a whole different competition (from Saturday) and whole different team that we’re going to be up against in the Gold Cup,’’ said Jozy Altidore, who started up top next to fellow New Jersey product Juan Agudelo. “It’s a totally different game so it’s a totally different mindset…Going into Canada, we have to be a little bit more confident and be the team to force the issue.”

Perhaps they’ll be better able to do that with Bradley, Dempsey and Donovan returning to a midfield that leaked possession against Spain. Donovan _ whose dozen career Gold Cup goals are more than the rest of the roster combined (9) _ practiced yesterday and showed no signs of the illness that knocked him out of Saturday’s lineup, and Michael Bradley showed how valuable he is by his absence.

It remains to be seen who he’ll play alongside, with Rangers’ Maurice Edu or Blackburn’s Jermaine Jones both excelling for club but struggling for country. Benny Feilhaber won’t be a possibility, injured in New England’s May 28 loss to Donovan’s Galaxy team and replaced on the roster today by Alejandro Bedoya, who weas born in Englewood and played two years at FDU.

“We’ll just have to try to look closely at ourselves,’’ the younger Bradley said. “As we move forward, not only in the Gold Cup but also in qualifying and hopefully the World Cup down the road, experiences (like Spain) will help us.”

It may take awhile to see how the experience helps down the road. Winning the 2007 Gold Cup earned them a spot in the 2009 Confederations Cup, where they upset Spain and had a 2-0 lead on Brazil in the final before losing. With little on the line two years ago, they fielded a young team and still reached the final; but expect Bob Bradley to take full aim at regaining the crown, starting Tuesday.

“We’ve always chosen to take these challenges and to play against the best teams, because it’s the best way to see what the game at the highest level is all about. It’s the best way for us to improve,’’ Bob Bradley said. “We know there are things that we can take from (Saturday) that will not only help us during the next three weeks, but help us as we keep trying to move forward.’’